Cellular resins reinforced with siliceous material



A. MARZOCCHI ETAL A ril 5, 1966 2 Sheets-Sheet 1 ed May 10, 1961 3 QMN v4% E M M C m 0F vrr O A M 0 v. E W B Am April 5, 1966 A. MARZOCCHI ETAL3,244,545

CELLULAR RESINS REINFORCED WITH SILICEOUS MATERIAL Filed May 10, 1961 2Sheets-Sheet 2 AL H250 M/mzoccw/ &

JAMES M. OFLAHAVA/v INVENTORS WQM AT TOR/V5 v.5

United States Patent 3,244,545 CELLULAR RESINS REINFORCED WITHSHIJICEOUS MATERIAL Alfred Marzocchi, Cumberland, and James M.OFiahavan, Manville, R.I., assignors to Owens-Corning FiberglasCorporation, a corporation of Delaware Filed May It), 1961, Ser. No.109,105 13 Claims. (Cl. 117-7) This invention relates to cellular orfoamed resins reinforced with siliceous elements and more particularlyto cellular resinous matrices which are reinforced by fibrous glassstrands.

Due to the inherent characteristics of limited flexibility andextensibility or elongation, poor resistance to compressive, flexuraland tensile stresses, and a marked susceptibility to extensive attritionresulting from mutual abrasion, fibrous glass yarns and fabrics have todate been restricted to static or non-dynamic applications such asdecorative fenestration fabrics and crude fabrics used in thereinforcement of rigid resinous structures.

These defects, together with a consumer antipathy toward the tactilequalities of such materials, have combined to prevent the utilization offibrous glass fabrics in such extensive, but dynamic, applications aswearing apparel, upholstery fabrics, carpeting and industrial fabrics.The specified consumer antipathy stems from a preference for the warmand dry tactile qualities evinced by non-synthetic fabrics such as wooland cotton.

In an attempt to upgrade the properties of fibrous glass fabrics,various attempts to coat either the yarn before weaving, or the finishedfabric, with a resin or similar material have been undertaken with onlylimited success. Satisfactory results have been precluded by the factthat such resinous coatings yield a stiff, rigidly bonded yarn or fabricwhich is prone to the harmful eifects of flexing, stretching and mutualabrasion while deterring the elongation or extensibility of the yarnsand providing a slick, cold feel which has been found repulsive to theconsumer.

In an attempt to overcome these obstacles or impediments, foamed orcellular coatings have also been applied to fibrous glass strands.However, such structures have still failed to yield adequate propertiesof durability, extensibility and resistance to mutual abrasion. Whilethe presence of the cellular coating may for a time prevent the abrasionof the exterior or circumferential fibers of the strand, the fibersembodied in the core or central portion of the strand are still exposedto this deleterious force. In turn, the damaging affects of flexing uponplural filament structures and compressive or tensile stresses are notprevented since the core of the strand is still of the same nature asthat of an uncoated or untreated strand. In addition, the coating failsto impart extensibility to the yarn although its discontinuous surfacedoes serve to enhance the tactile stimuli evoked by-bodily contacttherewith. The durability of the cellular coating material comprises afurther drawback in that such materials, if unreinforced, are highlysusceptible to nominal abrasion or wear.

It is an object of the present invention to provide fibrous glassstrands which are characterized 'by unusual qualities of flexibility,extensibility, durability and abrasion resistance, as Well as byoutstanding tactile properties.

A further object is the provision of elongate, weavable elementscomprising cellular, resinous matrices provided with a uniformreinforcement of glass fibers.

Another object is the provision of methods for the fabrication ofelongate, weavable elements comprising cellular, resinous matricesprovided with a uniform reinforcement of glass fibers.

These and other objects of the invention will hereinafter appear in amore detailed description and for purposes of illustration, but not oflimitation, in the accompanying drawing in which:

FIGURE 1 is a sectional view through a yarn processed in accordance withthe practice of the invention;

FIGURE 2 is a schematic view of a preferred method and apparatus for theconduct of the invention;

FIGURE 3 is a second embodiment of a method and apparatus for theconduct of the invention;

FIGURE 4 is a third embodiment of a method and apparatus for the conductof the invention; and

FIGURE 5 is a fourth embodiment of a method and apparatus for theconduct of the invention.

The aforegoing objects are attained 'by means of the thoroughimpregnation of fibrous strands with a foamable composition, and thesubsequent in situ foaming of the foamable composition.

It has been found that yarn structures exhibiting unusual qualities ofdurability, elongation and flexibility, and resistance to fiexural,compressive and tensile stresses and abrasion, as well as outstandingtactile qualities, may be prepared by means of the deposition, throughthorough impregnation and in situ foaming of a cellular resin betweenand about the individual fibers which are incorporated in the strand oryarn structure. Such a composite structure is depicted by FIGURE 1wherein a greatly enlarged sectional view through a yarn of thedescribed type is provided. It may be seen that the structure comprisesthree plied strands designated generally at 11, 12 and 13 with eachstrand embodying approximately 200 glass fibers 14. As is apparent, theplurality of fibers which were originally tightly grouped in a compactstrand structure have been dispersed throughout the cellular matrix 15as a result of the in situ foaming of the resin.

The structures achieved are characterized by ideal properties in thatlow modulus materials, uniformly reinforced by high modulus elements,are yielded. The low modulus, cellular resin serves to take upcompressive forces and consequently protect the fibers from. suchstresses, while an ideal tensile strength relationship is realized dueto the fact that the resin first assumes an applied longitudinal forcewith such force subsequently being assumed by the high strength fibersprior to the attainment of the breaking point or permanent distortionpoint of the resin. During the phase when the force is borne by theresin, the fibers are provided with an opportunity to align andconsequently mutually assume the total force. In the absence of such acondition, the total force is experienced by individual fibers duringthe phase of non-alignment, and such fibers are successively broken toprovide a tensile strength which is less than that available when all ofthe fibers are aligned to mutually assume the stress. In addition, theradial com pression of the cellular resin upon the application oflongitudinal stress, operates to impart elongation or extensibility tothe composite structure.

Also desirable is the protection against mutual abrasion Which isprovided by the presence of the cellular resin between individualfilaments and groups of filaments.

Still further, warm, dry, absorbent tactile qualities are yielded by thediscontinuous or porous surface of the resin which completelyencompasses the yarn or strand.

The thorough impregnation of the strand with the foamable material maybe achieved by several methods, although a tortuous path approachinvolving the utilization of spreader bars is preferred. This method isbest demonstrated by FIGURE 2 wherein an uncoated fibrous glass strand21 is passed into a receptacle 22 and submerged in a bath comprising afoamable material 23. The strand 21, while submerged, is conductedthrough a tortuous path composed of a plurality of staggered spreaderbars 24 which are positioned across the width of the receptacle 22beneath the surface of the foamable material 23 and perpendicular to thepath of the strand. Both horizontal and vertical spreader bars 24 may beemployed. Since the strand 21 is maintained under constant tension, theroughly cylindrical strand is flattened out as it passes around thespreader bars, as shown at 25, to the end that the individual filamentsembodied within the strand are dispersed or disrupted from theiroriginal, dense or tightly picked relationship to thereby permit thepenetration of the coating material. The repetition of such dispersionor disruption through the medium of a plurality of spreader bars 24,insures the complete or thorough penetration of the strand. The strand21 may then be passed through a die 26 which serves to remove excesscoating material from the exterior of the strand, and thence to an oven27 which serves to activate a blowing agent embodied in the coatingmaterial and thereby foam the material.

When large quantities of the coating material are desired, a secondapplication subsequent to the oven treatment may be utilized and may befollowed by a second curing or heat treatment. It has been found that asmuch as 40% by weight of the coating compositions of the eX amples setforth hereafter may be imparted by the single coating apparatus ofFIGURE 2. However a coating comprising 80% or more by weight of theyarn-coating composite may be achieved by merely placing a secondcoating receptacle and a second oven in line, after the first oven 27.The two coating materials in the plural coating system may employdifferent materials and a blowing agent may be employed in one or bothof the materials.

While the incorporation of liquid or solid blowing agents in the resinand the subsequent fusion or boiling of these agents to yield voidproducing gases is the preferred foaming method, other conventionalfoaming or pore producing methods may be utilized. For example, an inertgas may be incorporated in the resin under pressure, and the mixturethen exposed to the atmospheric pressures to expand the gas, or gasesgenerated by an inherent reaction such as the CO yielded by the actionof water on polyisocyanates during urethane formation or water vaporizedby the exothermic heat of phenolic resin preparations, may be employedto foam the resin.

It should be noted that previous techniques for the coating of fibrousstrands with resins, but without provision for the thorough penetrationof the strand, have resulted in structures characterized by closelygrouped filaments with only the exterior or circumferential filamentspossessing a resinous coating. The foaming of the resinous coating ofthe latter type of structure does not entail the dispersion of thereinforcing elements or fibers throughout the foam and results in a flexand abrasion prone strand which is encased in an unreinforced, lowmodulus foam.

While the tortuous path or spreader bar technique of FIGURE 2 ispreferred, other methods of strand disruption, coupled with a thoroughimpregnation, may be em ployed. Two of these methods are illustrated byFIG- URES 3 and 4.

FIGURE 3 schematically and sectionally depicts an alternative method forthe disruption of the fibrous strand wherein the strand 31 is exposed tothe fluid turbulence of a high pressure jet 32 immediately prior tosubmersion in the foamable coating material 33. This treatment may beeven further enhanced when the fluid disruptive force supplied by thejet 32 is an additional quantity of the foamable material employed asthe coating material 33, rather than a gas.

In still another method, as illustrated by FIGURE 4, the strand 41,While submerged in the foamable coating material 42, is passed betweenthe nip of two spaced, opposed rolls 43, which serve to achieve thelateral displacement of the bunched fibers embodied in the strand andconsequently facilitate the thorough impregnation of the strand 14 bythe foamable coating material 42. This effect may also be enhancedthrough the utilization of rolls 43 having porous or perforatecircumferences, and if desired the injection or pressurized feeding ofthe coating material through such pores or perforations may be adopted.

A further refinement of the apparatus of FIGURE 4 is depicted by FIGURE5 wherein the strand 51 is submerged in a foamable coating material 52and passed between the nip of rolls 53 which have fluted surfaces.

It should be noted that immersion techniques have been selected due tothe efficiency and ease of penetration of the strand which they provide.However, conventional methods of contact or spray impregnation such astransfer rolls, pads, apron applicators, sprays and jets may also beutilized, when coupled with methods or means which insure the opening ofthe fibrous bundle and the thorough impregnation thereof with thefoamable coating material.

It is not deemed necessary that the impregnation step achieve theopening or disruption and thorough impregnation of each fibrous bundleto the extent that each individual filament is coated, since thedisruptive force of the foaming action serves to further the penetrationor impregnation. However, the impregnant must penetrate between eachmajor fiber bundle, e.g., the individual strands of a plied yarn, inorder to adequately disperse the fibrous reinforcement and preclude theoccurrence of massive or predominant groups of bunched fibers.

The fibrous strands employed in the practice of the invention arepreferably, although not necessarily comprised of siliceous or glassfibers. This is due to the fact that the properties imparted to theproducts achieved are greatly enhanced in the case of fibrous glass.However, other fibrous materials such as cellulosic, mineral orsynthetic organic fibers may be similarly treated when it is desired toimpart a low density bulk or excellent tactile qualities to the strandor yarn, or to avoid the damaging effects of flex, tensile, compressiveand abrasive forces. The specific form employed preferably comprisescontinuous glass filaments grouped into a strand form or a plurality ofsuch strands plied into a yarn structure. The basic strand referred toconventionally comprises approximately 200 grouped glass fibers havingdiameters of between .0001 and .0007 inch. In addition to strands andplied strands, fibrous glass staple yarns, roving and spun rovingprovide base materials amenable to the treatments of the invention. Thefibrous glass strands utilized may be provided with conventional formingsize compositions such as starch, gelatin or resin-based sizecompositions since the disruptive force of both the coating operationand the subsequent foaming action of the coating material serves toovercome any bonding affect which may be imparted by the forming sizecomposition.

While vinyl polymers and copolymers are the preferred foamable coatingmaterials of the invention, other foamable compositions such aspolyurethanes, phenolic, ureaformaldehyde, cellulose acetate, styrenepolymers and copolymers, silicone and epoxy resins as well as elastomerssuch as butadiene and styrene or acrylonitrile copolymers, neoprene andnatural rubber may also be utilized. The selection of the solvent systemand blowing agent or method in each case, is naturally dependent uponthe resin employed and the processing conditions which are preferred ordictated.

A preferred foamable coating material includes the following ingredientswhich are quantitatively expressed in percentages by weight:

EXAMPLE 1 Polyvinyl chloride 51.4 Dioctyl phthalate 37.7 Epoxyplasticizer 2.7 Barium-cadmium-zinc stabilizer 2.0 Antimony oxide (flameretardant) 2.1 Azodicarbonamide pigment 4.1

Another suitable coating material is set forth in the following example:

The coating formulations of the invention may be enhanced by and areamenable to the addition of dyes, pig ments, plasticizers, emulsifiers,stabilizers and the like. In addition, it has been found that both thetactile qualities and the durability of the foamed materials, areimproved by means of the incorporation of short milled fibers in thecoating either through the medium of addition to the coating bath or byapplication and adherence prior to the setting of the coating. Whilemilled cotton fibers are a preferred material, short lengths of glass,cellulosic, mineral or organic fibers are also satisfactory.

In a preferred embodiment, the yarns or strands are coated and thecoating is immediately foamed. The yarns may then be woven into a fabricwhich is satisfactory in such form or the fabric may be subjected to acalendering process which serves to adhere the woven yarns at theirpoints of contact or intersection.

Alternatively, the yarns after coating may be merely dried or curedwithout foaming, or with only limited foaming, and foaming may beachieved after the yarns are woven into a fabric. This is achievedthrough a close control of the conditions of temperatures utilized andby the selection of a proper blowing agent or method. When the coatingmaterial is foamed after the preparation of the fabric, a relativelyimpermeable fabric is obtained if the foaming is achieved by passing thefabric through the nip of heated rolls, such as calendering rolls. Inthis fashion the foam is forced out into the fabric interstices due tothe restriction of its lateral movement by the rolls.

One highly desirable product yielded by the invention is a foamablemolding compound. This product may be prepared by coating fibrous glassstrands with a foamable resin without activating the blowing agent andthen chopping the strand into short lengths. The coated strand segmentsmay then be molded into a desired shape and the resinous coating foamedby means of the heat of the molding step or by other conventional meansof activation such as chemical reagents. Such molding materials orcompounds are preferably composed of chopped strand segments having alength of two inches or less.

It has been found that fabrics prepared in accordance with the inventionexhibit unusual utility as upholstering materials, tarpaulin likefabrics, utility or truck covers and the like.

It is apparent that new and useful textile materials exhibiting unusualqualities, and methods for their preparation, have been provided by thepresent invention.

It is further obvious that various changes, alterations andsubstitutions may be made in the compositions, methods and products ofthe present invention without departing from the spirit of the inventionas defined by the following claims:

We claim:

1. A method for the preparation of a low density, extensible fibrousglass yarn comprising thoroughly impregnating a bundle comprising aplurality of continuous glass fibers grouped in a substantially parallelrelationship with a foamable synthetic resin by opening said bundle tocoat each individual fiber, curing said resin, and foaming said resin tolaterally displace said fibers individually and disperse said fibersthroughout a cellular matrix comprising the foamed product of saidsynthetic resin.

2. A methodas claimed in claim 1 in'which said foaming and said curingare achieved concurrently.

3. A method as claimed in claim 1 in which said foamable synthetic resinis polyvinyl chloride.

4. A method as claimed in claim 1 in which said impregnation is achievedby conducting said glass fibers under tension through a tortuous pathcomprising spaced, staggered guide elements and in contact with saidguide elements which serve to divert the course of said fibers andsimultaneously to displace the arrangement of said plurality of glassfibers as a product of said tension exerted upon said fibers and saidcontact of said fibers with said guide elements, and applying saidfoamable synthetic resin to said fibers while said fibers are displaced.

5. A method as claimed in claim 1 in which said impregnation is achievedby exposing said fibers to fluid turbulence and immediately immersingsaid fibers in said foamable synthetic resin.

6. A method as claimed in claim 1 in which said impregnation is achievedby conducting said fibers through the nip of opposed, spaced rolls, saidnip being positioned beneath the surface of a liquid body of saidfoamable synthetic resin.

7. A method for the preparation of a fibrous glass fabric comprisingthoroughly impregnating a yarn consisting essentially of a plurality ofcontinuous glass fibers grouped in a substantially parallel relationshipwith a foamable synthetic resin by opening said yarn to coat eachindividual fiber, curing said resin, weaving a plurality of said yarnsto form a fabric, and foaming said resin to laterally displace saidfibers individually and disperse said fibers throughout a cellularmatrix comprising the foamed product of said synthetic resin.

8. A low density extensible fibrous glass yarn consisting essentially ofa plurality of strands, each strand being formed of individualcontinuous glass fibers dispersed in a substantially parallelrelationship throughout an elongate substantially cylindrical cellularmatrix, said matrix consisting essentially of the in situ foamed productof a synthetic resin coating upon said glass fibers, each of theindividual fibers being displaced from the other fibers of the strand bysaid resin.

9. A yarn as claimed in claim 8 in which said synthetic resin ispolyvinyl chloride.

10. A low density fibrous glass fabric consisting essentially of wovenwarp and weft elements, said warp and weft elements consistingessentially of a plurality of strands, each strand being formed ofindividual continuous glass fibers dispersed in a substantially parallelrelationship throughout an elongate substantially cylindrical cellularmatrix, said matrix consisting essentially of the in situ foamed productof a synthetic resin coating upon said glass fibers, each of theindividual fibers being displaced from the other fibers of the strand bysaid resin.

11. A method for the preparation of a fibrous glass fabric comprisingthoroughly impregnating a yarn consisting essentially of a plurality ofcontinuous glass fibers grouped in a substantially parallel relationshipwith a foamable synthetic resin by opening said yarn to coat eachindividual fiber, curing said resin, plying a plurality of said yarns toform a plied yarn, weaving a plurality of said plied yarns to form afabric, and foaming said resin to laterally displace said fibersindividually and disperse said fibers throughout a cellular matrixcomprising the foamed product of said synthetic resin.

12. A method for the preparation of a fibrous glass fabric comprisingplying a plurality of yarns comprising a plurality of continuous glassfibers grouped in a substantially parallel relationship, to form a pliedyarn, thoroughly impregnating said plied yarn with a foamable syntheticresin by opening said yarn to coat each individual fiber, curing saidresin, foaming said resin to laterally displace said fibers individuallyand disperse said fibers throughout a celular matrix comprising thefoamed product of 7 said synthetic resin, and weaving a plurality ofsaid plied yarns to form said fabric.

13. A low density fibrous glass fabric consisting essentially of wovenwarp and Weft elements, said elements consisting essentially of aplurality of plied yarns, said yarns consisting essentially of aplurality of strands each strand being formed of individual continuousglass fibers dispersed in a substantially parallel relationshipthroughout an elongate substantially cylindrical cellular matrix, saidmatrix consisting essentially of the in situ foamed product of asynthetic resin coating upon said glass fibers, each of the individualfibers being displaced from the other fibers of the strand by saidresin.

References Cited by the Examiner UNITED STATES PATENTS 1,667,408 4/1928Allen 117 2,176,835 10/1939 Cumfer 117-115 2,302,790 11/1942 Modigliani28-72 2,373,401 4/1945 King 117-126 2,639,759 5/1953 Simison 117-126Dacey et al.

Clougherty et a1. 117-126 Davis et al 117-62 Smith 260-25 Pinte et a1.117-126' Cocker 117-115 Muskat et al. 117-140 Shannon et al 117-126Lappala 161-93 Steckler et a1 117-126 Philipps 117-126 Morgan et al117-120 Wetterau 161-93 OTHER REFERENCES Steele: Fiber Glass-Projectsand Procedures, 1962, McKnight and McKnight Publ. (30., Bloomington,111.,

pp. 12 and 34-36.

20 WILLIAM D. MARTIN, Primary Examiner.

MURRAY KATZ, RICHARD D. NEVIUS, Examiners.

1. A METHOD FOR THE PREPARATION OF A LOW DENSITY, EXTENSIBLE FIBROUSGLASS YARN COMPRISING THROUGHLY IMPREGNATING A BUNDLE COMPRISING APLURALITY OF CONTINUOUS GLASS FIBERS GROUPED IN A SUBSTANTIALLY PARALLELRELATIONSHIP WITH A FOAMABLE SYNTHETIC RESIN BY OPENING SAID BUNDLE TOCOAT EACH INDIVIDUAL FIBER, CURING SAID RESIN, AND FOAMING SAID RESIN TOLATERALLY DISPLACE SAID FIBERS INDIVIDUALLY AND DISPERSE SAID FIBERSTHROUGHOUT A CELLULAR MATRIX COMPRISING THE FOAMED PRODUCT OF SAIDSYNTHETIC RESIN.